<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CSS样式引入</title>
    <style>
      h2 {
        color: chartreuse;
        font-weight: lighter;
      }
    </style>
  <!-- 引入外部的CSS文件 -->
  <link rel="stylesheet" href="my.css">
</head>
<body>
  <h1 style="color: rebeccapurple; font-style: italic">内联式样式</h1>
  <h2>内部样式1</h2>
  <h2>内部样式2</h2>
  <h2>内部样式3</h2>
  <h3>外部样式1</h3>
  <h3>外部样式2</h3>
</body>
</html>